User`s guide

Chapter 14 The Certificates Screens
User’s Guide
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A certification path is the hierarchy of certification authority certificates that validate a
certificate. The WiMAX Modem does not trust a certificate if any certificate on its path has
expired or been revoked.
Certification authorities maintain directory servers with databases of valid and revoked
certificates. A directory of certificates that have been revoked before the scheduled expiration
is called a CRL (Certificate Revocation List). The WiMAX Modem can check a peer’s
certificate against a directory server’s list of revoked certificates. The framework of servers,
software, procedures and policies that handles keys is called PKI (public-key infrastructure).
14.4.1.1 Advantages of Certificates
Certificates offer the following benefits.
• The WiMAX Modem only has to store the certificates of the certification authorities that
you decide to trust, no matter how many devices you need to authenticate.
• Key distribution is simple and very secure since you can freely distribute public keys and
you never need to transmit private keys.
14.4.1.2 Self-signed Certificates
You can have the WiMAX Modem act as a certification authority and sign its own certificates.
14.4.1.3 Factory Default Certificate
The WiMAX Modem generates its own unique self-signed certificate when you first turn it on.
This certificate is referred to in the GUI as the factory default certificate.
14.4.1.4 Certificate File Formats
Any certificate that you want to import has to be in one of these file formats:
• Binary X.509: This is an ITU-T recommendation that defines the formats for X.509
certificates.
• PEM (Base-64) encoded X.509: This Privacy Enhanced Mail format uses lowercase
letters, uppercase letters and numerals to convert a binary X.509 certificate into a printable
form.
• Binary PKCS#7: This is a standard that defines the general syntax for data (including
digital signatures) that may be encrypted. A PKCS #7 file is used to transfer a public key
certificate. The private key is not included. The WiMAX Modem currently allows the
importation of a PKS#7 file that contains a single certificate.
• PEM (Base-64) encoded PKCS#7: This Privacy Enhanced Mail (PEM) format uses
lowercase letters, uppercase letters and numerals to convert a binary PKCS#7 certificate
into a printable form.
A Be careful to not convert a binary file to text during the transfer process. It is
easy for this to occur since many programs use text files by default.